Hydraulic actuator with integrally housed valve



Oct. 30, 1962 D. M. BLAND EIAL 3,060,901

HYDRAULIC ACTUATOR WITH INTEGRALLY HOUSED VALVE Filed May 31, 1960 In NFIG 2 DAVID M. BLAND BY RICHARD H. MYERS AGENT United States Patent3,060,901 HYDRAULIC ACTUATOR WITH INTEGRALLY HOUED VALVE David M. Bland,Dallas, and Richard H. Myers, Arlington, Tex., assignors, by mesneassignments, to Linggezsncc-Vought, Inc, Dallas, Tex., a corporation ofaaware sites May 31, 1960, Set. No. sass? 7 Claims. or. 121-465) Thisinvention relates to hydraulic motors and valves and more particularlyto an improved construction or arrangement comprising a hydraulicactuator and valve.

In many applications wherein a hydraulic actuator is employed inconjunction with a remotely controlled valve, prompt and uniformlyaccurate response of the actuator to a given change in valve setting isvitally essential. Especially where a high-pressure hydraulic system isutilized for supplying fluid to the actuator through the valve, thespringiness or compliance of the hydraulic connection between the valveand actuator barrel has been deleterious to prompt and accurate actuatorresponse. Thus, where hydraulic fluid is admitted by a valve through atube or pipe to the barrel of an actuator which, to operate, must move alarge load, the pipe walls tend to undergo an elastic increase indiameter and the column of fluid in the pipe acts as a fluid spring. Acertain amount of fluid and time, therefore, is expended in building upthe spring-loading in the fluid and pipe until it is of suflicientmagnitude to overcome the load which must be moved by the actuator.

To alleviate this and other difliculties, hydraulic servo valves havebeen mounted directly on the actuators which they control in order tomake the hydraulic connections between the valve and the barrel of theactuator as short as possible and thus reduce the springiness of thecolumn of hydraulic fluid. Also, the walls of the passage or passagesconnecting the barrel and valve have been made rigid and free ofspringiness by forming them integrally in the relatively thick and rigidmaterial of which the barrel is made. The interests of compactness ofinstallation, etc., also are served Where the barrel passages and thenecessary conduits connecting the valve with the pressure and returnlines of a hydraulic system have been formed integrally in the barrelwall and where the valve is mounted directly on the actuator.

To connect the valve to these passages, an arrangement has been employedwherein a flat face is formed on the barrel, and all the passages openoutwardly through respective ports grouped within this flat. A similar,flat face is formed on the valve housing, and in it are grouped thevalve ports in such an arrangement that, when the faces are placedtogether, the valve ports mate with the corresponding ports in thebarrel face. The hydraulic connection at each port is sealed with acircular washer or O-ring which surrounds it and is set into the barreland/ or valve face.

The result, as intended, is a short, rigid hydraulic connection betweenthe valve and actuator and a compact, unitary disposition of thehydraulic passages to and from the valve. Several serious disadvantages,however, accrue to the above-described arrangement. The valve is exposedto mechanical and thermal damage. Bolts or the equivalent must beemployed for holding the valve face tightly and precisely engaged withthe actuator barrel face, and these must be torqued very carefully toobtain and maintain a true fit and thereby ensure proper sealing. Themating surfaces of the valve and barrel must be made to very closetolerances, and this is difficult in the case of flat surfaces. TheO-rings employed around each port form face seals, and since thehydraulic pressure exerted V 3,066,9hl Patented Oct. 30, 1962 on them isradially outward, it stretches and increases the diameter of the O-ringand'reduces its cross-section, thus diminishing its effectiveness as aseal. Each Q-ring is an external, oil-to-air seal, and any leakage pastit is an external leakage.

It is therefore an object of the present invention to provide acombination hydraulic actuator and control valve therefor in which thevalve is better protected from mechanical and thermal damages.

Another object is to provide a combination valve and actuator in whichflat mating surfaces and face seals between the valve and actuator areeliminated and external seals are reduced in number.

A further object is to provide a valve and actuator wherein mounting thevalve is more quickly and conveniently accomplished and wherein there islessened likelihood of leakage of hydraulic fluid.

Yet another object is to provide a valve and actuator in which the valvehousing is integral with the actuator barrel and in which all sealingsurfaces are annular and internal to the housing.

A still further object is to provide a valve housing integral with anelement of a hydraulic actuator and in which, if desired, the valve bodymay be shrink-fitted into the housing.

Other objects and advantages will be obvious from the specification andclaims and from the accompanying drawing illustrative of the invention.

In the drawing:

FIGURE 1 is a perspective, partially cut-away view of the actuator,integral housing, and valve assembly;

FIGURE 2 is a plan view of one end of the actuator showing the valvehousing in longitudinal section as in a plane designated by the line andarrows II-II in FIG- URE 1;

FIGURE 3 is a. similar view taken in a plane indicated by the line andarrows III-III in FIGURE 1;

FIGURE 4 is a view similar to FIGURE 2 and showing the valve assembly inplace in the housing; and

FIGURE 5 is a view similar to FIGURE 4 and in which the valve assemblyis shrink-fitted into the housing.

With initial reference to FIGURE 1, the hydraulic actuator 10 has abarrel 11 formed of a metal or other suitable material which encloses achamber 12 in which a piston 13 is slidably mounted. A rod 14 which isconnected to one face of the piston 13 and which extends outwardly fromone end of the barrel 11 causes the piston face to which it is joined tobe smaller in area than the opposite face of the piston. In theparticular example shown, the smaller face of the piston 13 iscontinually supplied with hydraulic pressure by a passage 15 which iscast, drilled, or otherwise formed in material integral with the barrel11 and which has an opening into the chamber 12 at or near its end fromwhich the piston rod 14 emerges. The pressure passage 15 opens to theouter surface of the barrel 11 at, for example, one side of the end ofthe barrel from which the piston rod 14 extends, and the opening isadapted for connection, with a hydraulic pressure line (not shown)leading to a hydraulic pressure source, by any desired means such as,for example, threading the opening as at 16 to receive a standardhydraulic tube attachment fitting. A branch 17 of the pressure passage15 is routed through material integral with the barrel 11 to the valvehousing 18 and opens into the latter as will be described.

A return passage 20 similarly formed in the material of the barrel 11has an opening which is located as at 19 in the outer surface of thebarrel and also is adapted for connection with a line, in this case thereturn line (not shown) of a hydraulic system. From its opening 19, thereturn passage 20 leads to the valve housing 18 by a route which,neglecting differences in length, preferably lies opposite andsymmetrically matches the path of the pressure passage 17. In additionto the pressure and return passages 17, 20, at least one other passageis integrally formed in the material of the barrel as at 21 (FIGURE 3)and is described in a later paragraph.

The housing 18 is of one-piece construction and is cast or otherwisereduced in one integral piece with the barrel 11. As seen in FIGURE 2,the housing 18 has a cavity 23 which is cylindrical about an axis 22.One end of the cavity 23 preferably is closed either by a portion 24(FIGURE of the material of which the housing 18 and barrel 11 are madeor by closure means such as a transversely extending plate 25 (FIGURE 2)seated against an annular shoulder in the cavity 23 and held in place:by a lock ring 26 seated in a groove adjacent the shoulder or by othersuitable fastening means. The cavity 23 has an end opening 28 surroundedand defined by a flat face or shoulder 27 of the housing. In thepreferred example, this face 27 is surrounded by a cylindrical,internally threaded wall 29 made of the material of the housing 18 andbarrel 11 and forming a larger-diameter, open-ended auxiliary cavity 30coaxial with the valve cavity 23.

With continued reference to FIGURE 2, the pressure and return passages17, 20 have communication with the :valve cavity 23 through respectiveopenings 31, 33 formed in the material of the barrel 11 and housing 18and leading into the cavity 23. These openings 31, 33 are axially spacedfrom each other along the cavity axis 22, and between and axially spacedfrom them is at least one opening 32 which leads, through the at leastone other passage 21 (FIGURE 3) previously mentioned, into the barrelchamber 12. The length of this at least one other passage 21 should bekept as short as possible. In the preferred example, one end of thebarrel chamber 12 is constantly supplied with hydraulic pressure throughthe passage branch 15 (FIGURE 1), and the housing 18 is so locatedaxially of the barrel 12 that the opening 32 is in register, as shown inFIGURE 3, with the closed end of the barrel chamber 12. It is ofimportance that a common wall portion 34 (FIGURE 3) separates the barrelchamber 12 and valve cavity 23 and that the valve cavity opening 32 islocated as described, for by connecting the opening 32 into the chamber12 through the passage 21, which preferably is formed perpendicular tothe axis of the barrel cavity, the shortest possible passage forconnecting the valve cavity opening 32 to the barrel chamber 12 isprovided. The passage 21, accordingly, has the advantage of being veryshort, and it need have no axial extension at all relative to the barrelchamber 12. It further will be noted that no fittings or seals whateverare required in connecting the barrel chamber 12 to the valve cavity 23or the pressure and return passages 17, 20 into the valve cavity, andthis is a significant advantage in increasing the reliability ofoperation of the actuator in that a number of potential leak-points arethereby eliminatedflhe pressure, return, and barrel passages 17, 20, 21will be understood to constitute means connecting the correspondingcavity openings 31, 33, 32 to the pressure and return lines of ahydraulic system and to the barrel cavity.

With added reference to FIGURE 4, the valve assembly 35 is anelectrohydraulic unit with a cylindrical body 36 having an imperforateend wall 37 through which, since it is closed, no leakage can occur. Atits other end, the valve body 36 has a shoulder portion 38 and a flatface on which is mounted the valve motor 39 which preferably is ofsmaller diameter than the shoulder 38. When inserted in the valve cavity23, the closed end Wall 37 of the valve body lies adjacent the plate 25closing an end of the cavity 23, and the shoulder 38 lies on the housingshoulder 27 and forms a stop means which precisely locates the valvebody 36 in a desired position along the axis 22 of the cavity. Anexternally threaded retainer ring 40 engages the threads of the housingwall portion 29 and bears against the valve body shoulder 38 to hold itfirmly in place against the housing shoulder 27, which closes off theopen end of the valve cavity 23. Since it only needs to he slipped intoplace within the valve cavity 23 and the retainer ring 40 tightened, thevalve assembly is quickly and easily mounted and connected to theactuator 10' and hydraulic pressure and return passages 17, 20. Totallyenclosed in the valve cavity 23, the valve body 36 is well protectedfrom mechanical damage from blows, etc. The valve housing 18 andactuator barrel 11 form a heat sink and shield for the valve body 36which protects it from sudden rises in ambient temperature. Protectionalso is afforded the valve motor 39 by the wall portion 29 forming theauxiliary cavity 30, and the latter is readily enlarged to totallyenclose the motor.

The valve body 36 has, in its cylindrical sidewall, the same number ofports as there are openings into the valve cavity; thus, in theparticular embodiment shown, the valve body has pressure, return andbarrel chamber ports 41, 43, 42 each lying in register, along the axis22 of the valve cavity 23, with a respective pressure, return, or barrelchamber passage opening 31, 33, or 32 into the valve cavity 23. Each ofthese ports 41, 42, 43 communicates with the interior of the valve body36. For each port 41, 42, 43 there preferably is supplied a respectivegroove 44, 45, or 46' in which the port lies and which extendscircumferentially of the valve body 36, the diameter of the latter, inthe specific embodiment shown, being slightly less than that of thevalve cavity 23. Since the grooves 44, 45, 46 are in register with thevalve ports 41, 42, 43 and the latter in register with the housingopenings 31, 32, 33, each opening communicates directly with arespective groove 44, 45, 46 and through the latter with a valve port41, '42, or 43.

On each side of each of the grooves 44, 45, 46 is a seal retainer groovein which is mounted an annular sealing means, such as an O-ring 47,expandable metal ring, or other suitable sealing device made of aresilient material. Each O-ring 47 extends circumferentially of thevalve body 36 and is radially compressed between the latter and the Wallof the valve cavity 23. An annular seal 47 accordingly is located oneach side of each of the openings 31, 32, 33 into the valve cavity 23.

To obviate damage to the O-rings 47 when inserting the valve body 36into the cavity 23, the cavity openings 31, 32, 33 preferably arelocated in the bottoms of cavity wall grooves, such as 48 (FIGURE 2)whose corners are chamfered. The O-rings 47 (FIGURE 4) thus do not comeinto contact, when the valve body 36 is inserted into the housing cavity23, with any sharp edges which may occur at the openings 31, 32, 33 inthe cavity wall.

The grooves in the valve body 36 and housing 18 at the pressure passageopening 31 constitute a chamber which is filled with hydraulic fluidunder the relatively steady pressure of a hydraulic pressure source.This chamber is closed at each of its ends by a respective one of theO-rings 47, and the sum of the hydraulic forces on each 0-ring 47 is inan axial, not a radial, direction. As a consequence, the ring 47 is notstretched, expanded outwardly, and diminished in its cross-section;instead, it is compressed axially and forced the more tightly intocontact with the housing 18 and valve body 36. The same result isobtained at the other O-rings 47 sealing off and isolating the barreland return openings 32, 33. The valve body 36, accordingly, need not bebolted down for forcing the rings 47 into fluid-tight contact with thevalve body 36 and housing 18. In a valve making a flat face seal with anactuator barrel, the hydraulic fluid exerts, at every port, a forcestrongly urging the separation of the valve and barrel, which force mustbe resisted by attaching bolts. In the present case, the net forceexerted by the hydraulic fluid on the valve body 36, both radially andaxially of the housing 18, is zero; therefore, no need at all exists forfastening means employed to resist hydraulic forces. Since the sealbetween the valve body 36 and housing 18 is efiected by the resilientO-rings 47, it is not critical that the valve body 36 be of a preciselyexact diameter, and it may be made to wider tolerances than may beemployed where a. flat face seal is made between a valve and barrel.

In a valve employing a face sealing arrangement with an actuator, eachof the seals employed is an ai-r-to-oil seal, one seal for each way inthe valve. It will be appreciated that, in the present construction,there are only two air-to-oil seals, i.e. at the two endmost ones of theO-r-ings 47. In a four-way valve employing the present construction,accordingly, there are only two air-to-oil seals; the rest areoil-to-oil seals at which leakage, if any should occur, can only beinternal of the hydraulic system. Furthermore, the two endmost ones ofthe O-rings 47 seal hydraulic fluid which is at the relatively steadypressures of the pressure and return sides of the hydraulic system andhence are least likely to experience failure resulting in leakage. Theactuator chamber pressure has the greatest fluctuation and is the mostpredisposed to causing O-ring failure. This pressure is sealed by theones of the O-rings 47 lying to either side of the barrel chamber port42 (FIGURE 4) which, as explained, can leak only internally of thehydraulic system.

The valve body 36 contains flow-controlling parts and passages which,under control of an electrical signal supplied to the motor 39, regulateand govern the flow of hydraulic fluid through the pressure passageopening 31, valve body pressure and chamber ports 41, 42, and chamberpassage opening 32 into the barrel chamber 12 or, as dictated by asignal received by the motor 39, out o f the chamber 12 through thechamber passage opening 32, valve body chamber and return ports 42, 43,and return passage opening 33. Since such valve parts and theelectrohydraulic control means and electrical connections therefor arewell known and form no part of the present invention, they need not beshown or described herein, for they can readily be provided by oneskilled in the art, to whom their form and operation will be well known.

Hydraulic fluid supplied under pressure to the opening 16 of thepressure passage is continually admitted to the smaller-area face of thepiston 13 through the passage 15 and to the valve pressure port 41through the passage branch 17 and opening 31. It will be noted thatthere is free communication between the port 41 and opening 31 becauseeach opens into the annular chamber enclosed between the O-rings lyingon each side of the port 41 and passage opening 31. A hydraulicallyexerted force therefore is continuously imposed on the piston 13 in adirection urging retraction of the piston rod 14, and hydraulic fluidunder pressure is continuously supplied to the valve pressure port 42.Upon energization of the motor 39 for connecting the pressure port 41internally of the valve with the chamber port 42, fluid flows from thelatter and through the passage 21 (FIG- URE 3) with opening 32 into theactuator barrel chamber 12 at the larger-area side of the piston 13.Since both faces of the piston 13 thus are supplied with the samepressure, the force applied to the larger-area face of the piston 13prevails, and the piston rod 14 is extended. Upon energization of themotor 39 for closing off internal communication between the valvepressure and chamber ports 41, 42, the piston is hydraulically locked inposition. Energization of the motor 39 for causing connection of thechamber port 42 internally of the valve with the valve return port 43places the larger face of the piston 13 under the return line pressureof the hydraulic system employed, and (the force exerted on thesmaller-area face of the piston being then the greater) the piston ismoved to retract the rod 14. The retraction expells fluid from thebarrel through the passage 21 (FIGURE 3) With opening 32, valve chamberport 42 and return port 43 (FIGURE 4), return port 33, and returnpassage 20,

the latter having a terminal opening 19 (FIGURE 1) adapted forconnection into the hydraulic system return line. Reference is made, forexample, to the U.S. Patents 2,767,689 and 2,625,136 issued on October23, 1956 and January 13, 1953 to William C. Moog, Ir., which patentsshow arrangements of valve parts and control means that one skilled inthe art will readily employ in the valve assembly 35 for the purposesenumerated above. The drawing accordingly shows only the ports 41, 42,43 opening into the interior of the valve and providing hydraulicconnection with the conventional interior parts of the valve.

In the modification shown in FIGURE 5, the O-rings are omitted from thevalve body 36A and the latter is made to a diameter enabling it to beshrink fitted into the valve cavity 23 and providing, after the shrinkfitting, a fluidtight seal effected by the annular sealing means formedby the annular parts of the valve body such as 47A lying on each side ofthe grooves 44, 45, 46 and the ports 41, 42, 43 therein. When thisconstruction is employed, the annular sealing means 47A are integralwith the valve body 36A, and the latter becomes, for practical purposes,one piece with the housing 18 so that O-rings are not needed andproblems of wear and deterioration of seals between the valve body 36Aand the wall of the housing 18 are entirely eliminated. As shown, theclosure plate 25 (FIGURE 2) may be omitted and its place taken by anintegral end-wall portion 24 of the housing 18.

While only one embodiment of the invention, together with a modificationthereof, has been described in detail herein and shown in theaccompanying drawing, it will be evident that various furthermodifications are possible in the arrangement and construction of thecomponents employed without departing from the scope of the invention.

We claim:

1. In combination;

a hydraulic actuator having a piston and a one-piece body of materialforming a chamber in which the piston is slidably mounted, said materialhaving an exterior surface;

a cylindrical cavity in said material, said cavity having an axis, aclosed end, and an open end;

passages which lead to the exterior surface of the material and at leastone of which opens into the chamher;

at least one other passage, all of said passages being integrally formedin said material;

a plurality of openings in said material mutually spaced along the axisof and leading into said cavity and each of the passages havingcommunication, through a respective one of the openings, with thecavity;

a valve assembly rigidly mounted in the cavity, said assembly having abody with a cylindrical outer surface and further having an imperforateend surface lying within the cavity and axially spaced from the cavityopen end;

a portion of said body spaced from the end surface and closing off theopen end of the cavity;

ports in the valve body each located, along the axis of the cavity, inregister with a respective one of the openings into the cavity;

and annular sealing means extending circumferentially of the valve bodybetween the latter and the wall of the cavity on each side of each ofthe openings into the cavity.

2. In combination with a hydraulic actuator having a barrel with anexterior surface and an inner chamber and a piston slidably mounted inthe chamber:

a housing made in one integral piece with said barrel and having acylindrical cavity with an axis and at least one open end;

passages leading to the exterior surface of the barrel and at least oneof which opens into the inner chamber of the barrel;

in addition to said passages, at least one other passage,

all said passages being integrally formed in the material of the barreland housing;

a plurality of openings in said housing, said openings being spacedalong the axis of and leading into the housing cavity and each of thepassages having communication through a respective one of the openingswith the cavity;

a valve assembly having a body with a cylindrical outer surface, saidbody being rigidly mounted in the cavity;

ports in the body each located, along the axis of the cavity, inregister With a respective one of the openings into the cavity;

and a plurality of annular sealing means extending circumferentially ofthe body between the cylindrical outer surface of the latter and thewall of the cavity on each side of each of the openings into the cavity.

3. In combination with a hydraulic actuator of the type having a pistonand a barrel with a chamber enclosing the piston and further having apair of integrally formed passages adapted for connection, respectively,with a hydraulic pressure line and a return line and at least one of thepassages communicating with the chamber, the construction comprising:

a housing made in one integral piece with said barrel and having acylindrical cavity with an axis and at least one open end;

an electrohydraulic valve assembly having a cylindrical body rigidlymounted in the cavity and having an end lying Within the cavity;

a plurality of openings in the housing into the cavity, the openingsbeing spaced along the cavity axis and each of the passages havingcommunication through one of the openings with the cavity;

ports in the valve assembly body each located, along the axis of thecavity, in register with a respective one of the openings into thecavity;

a plurality of annular sealing means extending circumferentially of thebody between the cylindrical outer surface of the latter and the wall ofthe cavity on each side of each of the openings into the cavity;

a shoulder on said body disposed in closing relation with the at leastone open end of the cavity;

and means extending across and in closing relation to the cavityadjacent the end of said body lying within the same.

4. The combination claimed in claim 3, said annular sealing means beingmade of a resilient material.

5. In combination with a hydraulic actuator of the type having a pistonand a barrel with a chamber enclosing the piston and further havingintegrally formed passages adapted for respective connection withhydraulic pressure and return lines and at least one of the passagescommunicating with the chamber, the construction comprismg:

a housing made in one integral piece with said chamber and having acylindrical cavity with an axis;

an electrohydraulic valve assembly having a cylindrical bodyshrink-fitted into the cavity;

a plurality of openings in said housing, said openings being spacedalong the axis of and leading into the housing cavity and each of thepassages having communication through one of the openings with thecavity;

circumferentially extending, annular grooves in the cylindrical bodyeach located, along the axis of the cavity, in register with arespective one of the openings into the cavity;

and a port located in each groove and leading into the interior of thecylindrical valve body.

6. In combination with a hydraulic actuator having a barrel portionenclosing a chamber and a piston slidably Cit mounted in the chamber,the construction comprising:

a housing formed integrally with the barrel and having a cylindricalcavity with an axis;

a pressure passage and a return passage formed integrally in the barreland opening into the cavity at respective points spaced apart along theaxis of the latter;

at least one other passage formed integrally in the barrel and openinginto the chamber enclosed thereby, said at least one other passageopening into the housing cavity between the points Where the pressureand return passages open into the cavity;

a valve assembly having a body with a cylindrical outer surface rigidlymounted in the housing cavity; ports in the valve body each located,along the axis of the cavity, in register with a respective one of theopenings into the cavity;

and a plurality of resilient, annular sealing rings extendingcircu-mferentially of the valve body between the cylindrical outersurface of the latter and the wall of the cavity on each side of each ofthe openings into the cavity.

7. A barrel enclosing a chamber having an end;

a piston slidably mounted in the chamber;

a valve housing having a cavity with an axis;

a well portion integral with both the barrel and the housing, said wallportion lying between and isolating, one from the other, the barrelchamber and housing cavity;

a pair of passages integrally formed in the barrel and housing;

means for connecting said passages respectively to pressure and returnlines of a hydraulic system;

a pair of openings in the housing into the cavity thereof, said openingsbeing spaced along the axis of the cavity and each providingcommunication between one of the passages and the cavity;

a third opening into the cavity spaced between the pair of openings andin register with the end of the chamber;

a passage extending through said wall portion and connecting the thirdopening with the chamber;

a valve assembly body rigidly mounted in the housing cavity;

ports in the body each located, along the axis of the cavity, inregister with a respective one of the openings into the cavity;

and a plurality of sealing means extending circumferentially of the bodybetween the latter and the housing on each side of each of the openingsin the cavity.

References Cited in the tile of this patent UNITED ST ATES PATENTS109,980 Weinman Dec. 6, 1870 234,649 Boland Nov. 23, 1880 476,228Hamilton May 31, 1892 574,415 Gunckel Jan. 5, 1897 860,434 Anderson July16, 1907 1,196,041 Smith Aug. 29, 1916 2,564,896 Gustafsson et a1 Aug. 21, 1951 2,699,756 Miller Jan. 18, 1955 2,718,877 Rishel et a1. Sept. 27,1955 2,786,454 Bertsch liar. 26, 1957 2,879,796 Hobbs Mar. 31, 19592,976,852 Goldring Mar. 28, 1961 FOREIGN PATENTS 1,090,829 France Oct.20', 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,060,901 I October 30, 1962 David M Bland et alo It is herebycertified that error appears in the above numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

Column 3, line 7, for "reduced" read produced column 8, line 26, for"well" read wall Signed and sealed this 26th day of March 1963 (SEAL)Attest:

ESTON G6 JOHNSON DAVID L. LADD Attesting Officer Commissioner of Patents

